Abstract

BENZAQUEM, Denise Corrêa et al. Rare translocation t(12;13) in a patient with dysmorphisms and developmental disorder. Rev Pan-Amaz Saude [online]. 2025, vol.16, e202501681.  Epub Oct 28, 2025. ISSN 2176-6215.  http://dx.doi.org/10.5123/s2176-6223202501681.

Translocations are simple structural variants of the genome, arising from simultaneous breaks in different chromosomes followed by incorrect rejoining of their ends. In some cases, they may disrupt haploinsufficient genes or regulatory regions, leading to clinical phenotypes. This report describes, to the best of our current knowledge, the first case of a balanced reciprocal translocation, t(12;13), associated with a pericentric inversion of chromosome 9 in a patient with dysmorphic features. The case involves a 6-year and 3-month-old male, the second child of a non-consanguineous couple. Physical examination revealed bitemporal narrowing, deep-set eyes, mild ocular hypertelorism, low-set and simplified ears, macrostomia, prognathism, protruding tongue, fifth finger clinodactyly, and flat feet. Cytogenetic analysis showed karyotype 46, XY, inv(9)(p12q13), t(12;13)(q13;q12). The translocation was confirmed by fluorescence in situ hybridization using whole-chromosome probes, where chromosome 12 was labeled with FITC (green) and chromosome 13 with CY3 (red). Comparative genomic hybridization by microarray revealed no loss or gain of genetic material, consistent with a balanced translocation. A detailed investigation of breakpoint regions in seemingly balanced rearrangements can provide important clues for identifying candidate genes linked to clinical phenotypes. Given the dysmorphisms observed, investigation of potentially involved genes is warranted. Additionally, cytogenetic studies of family members, particularly the parents, are crucial for determining the origin of the rearrangement and providing more accurate genetic counseling.

Keywords : Karyotype; Genetic Translocation; Comparative Genomic Hybridization; Congenital Abnormalities.

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